Indexes

Question 1

What is an INDEX?

Answer 1

An index is an in-memory structure that ensures that queries we run on a database are performant

Question 2

Most common algorithm type of index?

Answer 2

Binary-tree`

Question 3

Are PRIMARY KEY columns indexed by default?

Answer 3

TRUE

Question 4

Syntax for creating a single-column INDEX

Answer 4

CREATE INDEX index_name on table_name (column_name);

Question 5

What is the complexity of a binary tree?

Answer 5

O(log(n))

Question 6

Drawbacks of creating an index

Answer 6

1. Increases the memory usage of your database
2. Slows down your insert speed

Question 7

Syntax for creating a multi-column INDEX

Answer 7

CREATE INDEX first_name_last_name_age_idx
ON users (first_name, last_name, age);

Question 8

How SQL injections are prevented?

Answer 8

SQL library that sanitizes SQL inputs